Depression is a mental illness that affects roughly 1/5 of adults in the United States according to the 2002 National Comorbidity Survey Replication. Two types are widely recognized, share a number of symptoms and have similar causes.
Biology of Depression
The National Institute for Mental Health points out that depression is a brain disorder. People suffering from depression show abnormal brain function and an imbalance of brain chemicals.
Types
According to the Diagnostic and Statistical Manual, 4th Edition, there are two kinds of depression: major depressive disorder and dysthmia. Dysthymia is distinguished from major depression by lower level but more chronic symptoms.
Major Depression Diagnosis
Major depression entails feelings of sadness or, loss of interest in activities previously enjoyed lasting more than two weeks accompanied by at least three of the following: low energy, difficulty concentrating and/or making decision, irritability and/or restlessness, eating disturbances, sleeping disturbances and thoughts of suicide, hopelessness, worthlessness or guilt.
Dysthymia Diagnosis
Dysthymia entails an ongoing, low level depressed mood for most of the day, more days than not, over at least two years with at least two of the symptoms of major depression.
Causes
Although not fully understood, depression is most likely caused by some combination of genetic, biological and environmental factors such as family dynamics, poverty or divorce.
Tags: major depression